The invention relates to a method for processing a metal film which is embedded in a carrier, in particular a method for processing a component having a sandwich structure into which a metal film is embedded, such as, for example, a method for processing a component assembled by anodic bonding and having a metallic bonding electrode film. Furthermore, the invention relates to a component (assembly part) with a carrier and a metal film embedded in the carrier, in particular a component produced by the mentioned method. Applications of the invention are in the production of tools for holding or moving workpieces under the action of electrical fields or of resistive heating elements or in the marking of or pattern generation on glass components.
It is generally known that thin metal films (functional metal films) formed on the surface of electrically insulating substrates, such as, for example, formed on glass substrates, can perform numerous different functions. Thin metal films form, for example, transparent electrodes for the generation of electrical fields within the environment of the substrate, resistor elements for an electric resistive heating or provide for visually perceptible surface modifications of the substrate. In order to adapt the metal film on the substrate to the respective function, numerous methods for processing the metal film are known, such as, for example, targeted removal of areas of the metal film, in particular by ablation or etching.
Conventional applications of thin metal films generally have the disadvantage that a metal film on a substrate surface can be affected by environmental influences in a detrimental manner. In order to prevent this, a protective cover layer has to be formed on the metal film, which can only be performed after processing the metal film to adapt it to the respective function and represents an additional, possibly undesirable process effort.
An application of thin metal films is employed, for example, in tools for the handling of workpieces under the action of electrical fields, in particular tools for the handling of wafers in the semiconductor industry. A holding element (a so-called electrostatic clamp) for a wafer comprises a component in the shape of a flat plate on which at least two electrodes are disposed. When a high voltage is applied to the electrodes, an electrical field is generated in the environment of the electrostatic clamp, under the action of which a wafer is drawn to the clamp. For the duration of the application of the high voltage, the wafer can be moved with the clamp, for example, in a coating installation between different workstations. In the case of a conventional electrostatic clamp, the electrodes are formed by depositing a metal film on the surface of a carrier, subsequently structuring the metal film and covering the structured metal film with an insulating cover layer. This method is disadvantageous due to its complexity, in particular in the application with carriers consisting of anodically bonded carrier elements made of glass.
US 2007/0085337 A1 describes a multilayer security element comprising multiple plastic layers and a metal layer. Using a laser beam, identifiers are introduced into the metal layer, in the form of visual patterns, letters, numbers and/or images. By the effect of the laser beam, a changed modification of the metal, i.e., another metallic section, is obtained which has a changed reflectivity.
US 2002/0023901 A1 discloses a local laser processing of a metal being embedded in SiO2. Absorption of laser radiation results in a heating of the metal up to an expansion creating disruptions in the surrounding SiO2. The heated metal can evaporate through the disruptions leaving metal-free sections in the SiO2.
The objective of the invention is to provide an improved method for producing a component with a metal film, in particular for processing a metal film, by which the disadvantages of conventional techniques are avoided. By means of the method according to the invention, the targeted adaptation of the metal film to a predetermined function, such as, for example, the setting of a predetermined shape and/or surface area of the metal film, should be facilitated and/or a protection of the metal film from environmental influences should be improved. Furthermore, it is the objective of the invention to provide an improved component with a metal film by which the disadvantages of conventional components carrying a metal film are overcome. The component should be particularly suited for a reliable and reproducible adaptation of the metal film to the respective function and/or should guarantee a reliable protection of the metal film. The invention should in particular provide for new applications of functional metal films.
The mentioned objectives are achieved by a method and a component of the invention.